Creating vector line art of hexagon threaded fasteners in perspective.

We will start this Adobe Illustrator tutorial with the creation of a hexagonal shape (hex) by dragging the "Polygon" Tool (no keyboard shortcut) while holding the shift key to constrain it horizontally (Fig. 1). Once the shape has been created we will use the "Free Transform" tool to compress it vertically (Fig. 2). This step will determine the ratio of the perspective that will remain constant throughout this demonstration. In this case I have arbitrarily chosen a 20º ellipse ratio.

Technical Note: Start out with a very thin line thickness or "Weight" of around 0.15 pt. This will need to be manually entered in the "Stroke" dialogue box as the smallest native increment is 0.25 pt or 1/4 of a point. Note: The following hardware and software was used in this tutorial: Apple Mac Pro, a Wacom Intuos 6x8 drawing tablet and Adobe Illustrator CS-CS5 or CorelDRAW vector drawing software.

In Fig. 3 we will now add a circular ellipse to the center of the hexagon by changing the Polygon Tool to the "Ellipse" Tool (L). The circular ellipse should come into contact with all six center points of the hexagon's six facets.

The next step in or hex-head bolt drawing will be to cut the hexagon in half along the horizontal centerline (Fig. 4) by using the "Scissors" Tool (C). Once the hexagon has been bisected it is time to add anchor points to the center of all six facets (Fig. 5) using the Pen Tool.

Now we will Option>Drag the lower half of the hexagon in order to copy it to a new location (Fig. 6) using the Selection Tool (V). Use the Shift key to constrain its movement to a vertical plane. Next we will stat to activate each of the center anchor points along the hexagon (Fig. 7).

Once all of the center anchor points have been activated we will use the "Nudge" keyboard command (Arrow keys) to move the activated anchor points upward vertically (Fig. 8). The amount of movement for each keystroke will be determined by the setting you have chosen in Illustrator's "General" Preferences window. The Nudge command is affected by the "Keyboard Increment" box. This setting should be very low in order to make very small movements with each keystroke. I use a setting of .0010, but this is a personal preference.

Now we will smooth out the new corners that have been created by moving up the center anchor points (Fig. 9). For this task we will use the Pen Tool's "Convert Anchor point" Tool (Shift+C). We will click on each anchor point and drag the cursor to create a smooth edge. Pay attention to which way you drag the cursor, as this will effect the arc. This will be dependent on the direction of the stoke you are modifying.

Technical Note: You can speed up the movement by a factor of 10x when using the Nudge keyboard command by holding the shift key while pressing any of the arrow keys.

The next step will be to add the vertical divisions on the nut (Fig. 10). We will use the Pen tool to create a vertical line, and when it is the perfect length we will Option>Drag (duplicate) it to all four corner points along the foreground edge of the hexagon. When you make your first line be sure that it does not connect to the end anchor point of the hex. You can lock a path to prevent this from happening by activating it and pressing Command>2. To unlock all locked paths you can use the Command>Option>2 keyboard command or go to Object>UnlockAll in the menu bar.

Next we will add the washer under the hex head bolt by Option Dragging the upper ellipse to the lower surface of the nut (Fig. 11) and using Command>Shift>Drag to increase the size of the ellipse without changing the center point.

We will use the "Scissors" Tool (C) to cut the lower ellipse along its horizontal centerline (Fig. 12). Once the ellipse is bisected, we will Option>Drag the lower half of the ellipse to duplicate it to a lower position (Fig. 13) using the Selection Tool (V). This lower position will determine the thickness of the washer.

Next we will use the "Scissors" Tool (C) to cut the back side of the ellipse as it goes behind the hex bolt (Fig. 14). Once we have made both cuts, we will select it and use the Delete key to remove it. Now we will add the vertical lines on both sides of the washer (Fig. 15), again making sure that it does not connect to the end anchor point of the ellipse. You may need to lock the ellipse to accomplish this.

With all of the line work done, it is time to alter the line weights to make the nut and washer more readable. Start by selecting all of the outermost paths that surround the bolt/washer combination (Fig. 16). Using the "Stroke" dialogue box we will increase the line thickness of the outermost paths. In this case we have increased this line thickness or "Weight" to 0.5 pt or 1/2 of a point (Fig. 17). We will want a 200% to 300% increase in the thickness of the outermost line weights in relation to the inner line weights.

Now we will add a centerline to the bolt illustration (Fig. 18). This will be a hairline with a thickness of around 0.05. If you were to print this image this hairline should be very faint in the final printing. Next we will drag across the entire image using the Selection Tool (V) to activate all of the paths (Fig. 19). Make sure there are no paths that remain locked. Group the selection using Object>Group from the menu bar or Command>G on the keyboard.

Now we will use the Object>Transform>Reset Bounding Box command located in the menu bar. This will reset the "Bounding Box" to vertical and horizontal (Fig. 19) for all of the paths. Note: This is a very important step if you are going to rotate the image!

Once we have reset the Bounding Box we can use the "Free Transform" Tool (Fig. 20) or the "Rotate" Tool to rotate the image in any direction.

With the Bounding Box constrained to the same rotational axis as the bolt illustration, we can change the perspective ratio by elongating the Bounding Box along the centerline axis (Fig. 21). This will have the undesirable effect of stretching the height of the nut, so we will need to make a correction. To accomplish this, highlight all of the anchor points on the top surface of the nut. Drag them closer to the washer, keeping the centerline at the same angle.

Using this technique we can make one bolt and use it in several locations with different perspectives. This eliminates the repetitive task of re-drawing the bolt for each new perspective angle.